$-\dfrac{7}{5} + \dfrac{4}{2} = {?}$
Answer: $ = - {\dfrac{7 \times 2}{5 \times 2}} + {\dfrac{4 \times 5}{2 \times 5}} $ $ = - {\dfrac{14}{10}} + {\dfrac{20}{10}} $ $ = - \dfrac{{14} + {20}}{10} $ $ = \dfrac{6}{10}$